Hi i had my wheel of and inner plastic cover dvrs side at the weekend and i noticed an extra plug cable tied to the car not to sure but i`d say 80% its for the fogs as was in that location mines a 03 plate linnier. very very easy to check take wheel off and undo the plastic nuts and metal ones about 10 in all 7mm and 10mm pull it out and you will see about 1/2 hours work..
If your car didn't come with front fog lights, the head light switch will only have one extra button for the rear fog lights. There is a different switch available that adds a second button for the front fog lights. The switch is about $65.
I have an 05 9-3 and just added fog lights last weekend and the new switch. I took me about 4 hours from start to finish and really wasn't that hard. However, I did have to take the car to the dealership to have the software "turned on", and it took about 30 minutes and they only charged me $37.00, which isn't too bad in my opinion.
My car was already pre-wired, so all I had to do was connect it to the fog lights. I used the fog-lights installation instructions posted on the web - just search via google. It's a pdf file.
I purchased my stuff from patrick accessories. I looked around for a few months before I decided to buy, and found this place to have the best prices compared to any other website. Also put on a new muffler (the rear muffler for the twin exhaust), which only took about an hour, a vanity plate, lug nut caps, and bought some touch-up paint as well. All for under $500.00, which included shipping.